Ably

Realtime messaging service. Free for up to 20 simultaneous connections and 100,000 events/day

Communication infrastructure in 5 minutes. Free tier includes: 100 SMS and calls, 3000 Emails, Push, Slack, MS Teams, WhatsApp, and more.

Realtime messaging service, Pusher-compatible. Dev tier is limited to local development only and free with 100 concurrent connections, 1,000,000 broadcasts/month, unlimited client events, 32kb message size. ⬆️ Back to Top

Web Push Notifications - Free for upto 10k subscribers, unlimited push notifications, in-browser messaging

NATS.io as a service. Global, AWS, GCP, and Azure. Free forever with 4k msg size, 50 active connections, and 5GB of data per month.

SuprSend is a notification infrastructure that streamlines your product notifications with an API-first approach. Create and deliver transactional, crons, and engagement notifications on multiple channels with a single notification API. In free plan you get 10,000 notifications per month, including

SMS Gateway for Android™ enables sending and receiving SMS messages through your devices using cloud routing. Completely free cloud service (with recommended notification for usage above 10,000 messages/day to maintain quality for all users).

Realtime messaging service. Free for up to 100 simultaneous connections and 200,000 messages/day